Enhancement of Carotenoid Bioaccessibility from Tomatoes Using Excipient Emulsions: Influence of Particle Size

The effect of excipient emulsions with different lipid droplet sizes on carotenoid bioaccessibility from tomatoes was investigated using a simulated gastrointestinal tract (GIT). Excipient emulsions with different surface-weighted mean droplet diameters were fabricated: d ₃₂  = 0.15 μm (small), 0.40 μm (medium), and 22.3 μm (large). Changes in particle size, microstructure, ζ-potential, and carotenoid bioaccessibility were measured when tomato-emulsion mixtures that had received different thermal and mixing treatments were passed through the GIT model. Carotenoid bioaccessibility decreased with increasing initial droplet size (small ≥ medium > large), which was attributed to two effects. First, smaller droplets extracted carotenoids from tomato tissue more efficiently. Second, smaller droplets were digested faster leading to more rapid mixed micelle formation, thereby increasing carotenoid solubilization in intestinal fluids. Carotenoid bioaccessibility was higher from boiled than raw tomatoes because thermal disruption of the plant tissue facilitated carotenoid release. Carotenoid bioaccessibility was higher when tomatoes were boiled with emulsions than when they were boiled alone and then added to emulsions. In conclusion, excipient emulsions are highly effective at increasing carotenoid bioaccessibility from tomatoes, but lipid droplet size must be optimized to ensure high efficacy.

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